The invention relates to a high-frequency measurement setup and to a method for measuring a high-frequency test object, in particular, an antenna.
High-frequency (HF) test objects, in particular, antennas, such as, for example, satellite antennas, are analyzed in terms of their HF properties in high-frequency measurement setups and antenna measurement setups. An HF measurement setup, called Compensated Compact Range (CCR), has been created by the assignee to implement highly precise measurements of antennas. To implement the measurement, the setup supplies an HF signal that has a defined direction of propagation (boresight). Each HF test object, in particular, an antenna, must be aligned parallel to this HF signal in order to obtain the most exact measurements possible. Thus, a mechanical alignment of an HF test object is generally still necessary after the HF measurement setup has been installed.
Previously, at least two theodolites have been employed, as has been described, for example, in US/2009/0073061A1. The two theodolites measure corresponding orientation points on the HF test object and a mirror cube in the measurement setup for the direction of the HF signal, the mirror cube defining the direction of propagation of the HF signal. Time-consuming geometric-optical calculations must be performed in order to compute the alignment of the HF test object in terms of the HF signal's direction of propagation. The specular directions of the mirror cube of the measurement setup must be combined with the 3D coordinates of the HF test object in order to determine corresponding corrections in the rotations of the HF test object. One disadvantage of this method of measurement for adjusting the alignment of the HF test object is a relatively significant lack of precision in the in the individual measurements, as well as in a relatively imprecise alignment of the HF test object in the measurement setup in terms of the HF measurement direction (boresight). Another disadvantage is the high cost in terms of time and personnel in performing the measurements and determining the correction values for adjusting the HF test object.
Exemplary embodiments of the present invention provide an improved high-frequency measurement setup and an improved method for measuring a high-frequency test object, in particular, an antenna.
Exemplary embodiments of the present invention use a laser tracker to measure an HF test object, or one or more reflectors of a HF measurement setup, in terms of their direction of propagation (boresight) for HF signals. The alignment of the HF test object can be adjusted depending on the measurements—in particular, in such a way that deviations from a specified or desired alignment can be reduced. In order to effect an optimal measurement using laser trackers, retrotargets are provided on reflectors to define the propagation direction of an HF signal from a measurement setup for HF test objects, while retrotargets are provided on the HF test object to define the propagation direction of the HF signal from the HF test object such as an antenna. Retrotargets are reflectors that reflect an incident laser beam back—in particular, in its direction of incidence. Exemplary embodiments of the present invention provide a relatively precise alignment of an HF test object in terms of an HF measurement direction (boresight) and a significant reduction in the cost/effort required to align the HF test object as compared with the above-described method.
In one aspect, the present invention in fact involves a high-frequency measurement setup for measuring a high-frequency test object, in particular, an antenna, comprising
one or more reflectors for high-frequency signals
a laser tracker
retrotargets for laser beams of the laser tracker that are disposed on the reflectors and are provided to be disposed on the high-frequency test object,
and
a measuring unit that is designed to actuate the laser tracker in such a way that the high-frequency test object, and one or more reflectors, are measured in terms of their propagation of high-frequency signals (boresight).
The measuring unit can furthermore be designed to calculate and output correction values for the alignment of the high-frequency test object by using a best-fit transformation program based on the laser tracker measurements. The correction values can be displayed, for example, on a monitor, thereby allowing service personnel to align the high-frequency test object. The correction values can also be outputted through an interface for further processing by, for example, a control system of the high-frequency test object.
In addition, an adjustment device can be provided for the high-frequency test object, and the measuring unit can be designed so as to control the adjustment device in such a way that deviations are reduced in the propagation of high-frequency signals of the high-frequency test object from a specified alignment in terms of the propagation of the high-frequency signals from the reflectors. This approach enables a virtually automatic adjustment of the high-frequency test object in the measurement setup to be achieved.
Four retrotargets each can be provided on the high-frequency test object and on each reflector, the retrotargets being disposed at the corners or on edges of the high-frequency test object and of the reflectors.
The retrotargets can be designed such that they reflect an incident laser beam approximately back in the direction of incidence.
Another aspect of the present invention involves a method for measuring a high-frequency test object, in particular, an antenna, which method includes the following step:                Actuating a laser tracker, and measuring the high-frequency test object and one or more reflectors in terms of their propagation of high-frequency signals.        
In addition, the method can involve the following steps:                Calculating correction values based on the laser tracker measurements for aligning the high-frequency test object using a best-fit transformation program, and        Outputting the calculated correction values.        
In addition, the method can involve the following steps:                Controlling an adjustment device for the high-frequency test object depending on the measurements in such a way the deviations are reduced in the propagation of the high-frequency signals of the high-frequency test object from a specified alignment in terms of the propagation of high-frequency signals from the reflectors.        
In another aspect, the present invention involves a computer program for implementing the method according to the invention and as described above, when the computer program is implemented on a computer.
In addition, one aspect of the present invention involves a non-transitory data medium on which the computer program according to the invention, and as described above, is stored. The non-transitory data medium can be, for example, a magnetic or optical storage medium or a semiconductor storage mechanism. A non-transitory data medium can include a network data storage mechanism, for example, a server that is accessible through a computer network, such as, for example, the Internet. The computer program can be stored on this network storage mechanism for download to a local computer.
Additional advantages and applications of this invention are revealed in the following description in combination with the embodiments illustrated in the drawings.
The terminology used in the list of reference numerals provided at the back, and the associated reference numerals, are used in the description, in the claims, in the abstract, and in the drawings.